1. INCEDENCE AND CAUSES OF SUDDEN DEATH IN A UNIVERSITY HOSPITAL, EASTERN SAUDI ARABIA    
Houssien Kamel Nofal, MD, PhD1
Mohammed Fakhry Abdulmohsen, MD, MESC, FACC2
Ammar Hassan Khamis.Bsc, Msc, DEA and  PhD3

2. Introduction:
WHO definition of Sudden Death (SD) according to International Classification of Diseases (ICD-10) is the death occurring in < 24 hours from the onset of the symptoms, not otherwise explained and death is not to be violent.
The ultimate feedback on the accuracy of diagnosis of SD is the autopsy studies. However, postmortem studies are extremely limited in the KSA, which sometimes makes the diagnosis of SD a difficult task.

3. Introduction (cont’d):
SD can be instantaneous, sudden but not instantaneous, or cases where the individual is found dead.
It may occur at home, inside the transport or in bed during sleep.
It may occur in all categories of age, in infants (Sudden Infant Death Syndrome – SIDS), in children, in young's, in adults and in elderly.
The incidence and main causes of SD are variable from developed to developing countries.
Cardiopulmonary arrest is actually a sign of clinical death rather than a cause as it was widely believed by many practicing physicians.

4. Introduction (cont’d):
In 43%-51% of the cases, sudden cardiac death (SCD) was the leading identifiable cause of SD, and CAD was the most frequent cause for SCD (>70% of the cases).
In Japan, the commonest cause of SCD was cardiac arrhythmia.
Less common are deaths due to lesions of the central nervous system, pulmonary disease, sepsis and gastrointestinal or hepatic disease.
Epilepsy was a cause of SD in 10% of the cases occurring mainly during sleep.
About one third of SD remained unexplained after detailed medical investigations and 15.2% of the autopsies of SD failed to show the cause of death.

5. Introduction (cont’d):
The risk factors for SD include: older age, low and high (BMI), arterial hypertension, DM, smoking, sedentary life, unhealthy diet, and stress.
The incidence of SD in relation to all cause death was 41%, falling from 51% below the age of 50 years to 26% above the age of 80 years.
It appears also that the prodromal symptoms could be crucial in the prevention of SD.
Symptoms such as dizziness, syncope, palpitation and chest pain occur prior to death in 34% of cases.
There was also a seasonal variation in sudden death with the highest frequency occurring in winter (31%), followed by autumn (25%), spring (23%) and summer (21%).

6. Introduction (cont’d):
Unfortunately, there were no epidemiological or even hospital-based studies about the incidence, mode and causes of SD in Saudi Arabia.
In this retrospective descriptive study we are reporting on the frequency, the main causes, seasonal and diurnal variation of SD in relation to total death rate in KFHU, Eastern Region, Saudi Arabia during a period of 6 years (01/01/2000 to 31/12/2005).

7. Subjects and Methods:
This was a retrospective study of the medical files of all deceased patients during the study period.
Permissions from the Research Committees of the College of Medicine, UOD (former KFU), Dammam and KFHU, Al-Khobar, KSA were obtained.
The medical files of a total of 1273 consecutive cases of deaths were investigated.
Cases of sudden and expected deaths were analyzed, and the incidence and main causes of SD were reported.
The necessary statistical analyses to examine the relationship between variables were implemented. A P value of <0.05 was considered significant.

8. Results:
Out of the 1273 total deaths reported during the 6-year study period, there were 223 (17.5%) cases of SD and 1050 (82.5%) of expected deaths.
The males represented 56% of the cases of SD, and the Saudi nationality represented 74.4%.
The incidence of SD was high in the two age extremes [32.3% of the cases were infants, and 31.4% were elderly patients] and it was low among children and young adults [5.3% and 9.9% respectively].

9. Table 1: Age distribution of natural sudden death in KFHU (2000-2005)
Age groups
No. of cases of SD %
Infants (0-12 months) 72
31.2
Children and adolescents (1-18 years) 12
5.3
Young adults (19-39 years) 22
9.9
Middle aged (40-60 years) 47
21.0
Elderly (>60 years) 70
31.4

10. Results (cont’d)
There was a seasonal variation of SD with the highest incidence (29.6%) occurring during spring followed by summer (25.1%) with the lowest frequency during winter (22.0%, P < ).
There was also a diurnal variation with the highest incidence (31.8%) occurring at early morning hours (12:00 am to 5:59 am) followed by (26.46%) occurring at evening hours (6:00 pm to 11:59 pm) and the lowest frequency occurred during the afternoon hours (12:00 pm to 5:59 pm).

13.   Table 2: Important prior medical problems reported by the patients or their companions  
Past Medical History
No. of cases %
Diabetes mellitus Type 2 48
21.5
Hypertension 42
18.8
Cardiovascular disease* 34
15.2
Pneumonia 17
7.6
Sepsis
Cancer
Congenital anomalies** 15
6.7
Liver disease 14
6.3
Renal disease 7
3.1
Sickle cell disease and G6PD 2
0.9
*Including stroke
**Including Down's syndrome

14. Table 3: The most frequent prodromal symptoms on the initial presentation of cases of sudden death  
Initial symptoms
No. of cases of SD % 1.
Dyspnea 56
25.1 2.
Fever 26
11.7 3.
Premature infants 24
10.8 4.
Circulatory collapse 21
9.4 5.
Angina 17
7.6 6.
Cough 16
7.2 7.
Coma 12
5.3 8.
Anorexia 9.
Weakness 10
4.5
10.
Seizures 6
2.7
11.
Diarrhea 5
2.2
12.
Abdominal distension 2
0.9
13.
Dementia

15. Table 1: Direct causes of sudden death according to death certificates (2000-2005)
No. of cases of SD % 1
Cardiovascular Disease
132
59.1
CAD including AMI* 49
22.0
Hypertension 38
17.0
Stroke 16
7.1
Cardiogenic shock
Life-threatening cardiac arrhythmia 13
5.8 2
Respiratory Diseases 55
24.7
Pneumonia 29
13.0
Respiratory failure 6
2.7
Bronchial asthma 4
1.8
COPD** 3
Diabetes mellitus 53
23.8
Liver disease 52
23.3 5
Infectious Diseases 45
20.2
Renal Diseases 37
16.6 7
Congenital Anomalies 36
16.1 8
Cancer 9
Prematurity 28
12.6 10
Neuropsychiatric Diseases
4.5 11
Hematological Disease including sickle cell disease and hemophilia
2.2 12
Immunological Disorders including SLE and RA ***
* Coronary artery disease including acute myocardial infarction
** Chronic obstructive pulmonary disease
*** Systemic Lupus Erythematosus and Rheumatoid Arthritis

16. Discussion:
Natural SD is a major public health problem in our region similar to other parts of the world. It affected 17.5% of the total cases of death in a university hospital, Eastern Saudi Arabia.
This finding contrasts with the finding of Krahn et al., who reported an incidence of 41%.
In our study, SD was more frequent Among men than women (56% vs. 42%) and this is consistent with international experience.
The age distribution of SD is consistent with international experience.

17. Discussion (cont’d):
There was a seasonal variation of natural SD among our cases with the highest frequency during spring (29.1%), followed by summer (25.1%), then autumn and winter (22.8% each) and this contrast sharply with the findings of Katz and his colleagues who reported a peak incidence of SD during winter.
This might presumably be explained by the remarkable difference between the very cold weather during winter months in the northern half of the globe and the very hot, humid and dusty weather during the spring and summer months in our region .
In agreement with other researchers, the most frequent past medical problem was cardiovascular disease including CHD, hypertension, and stroke (34% of the cases).

18. Discussion (cont’d):
The most frequent prodromal symptoms in our study were: dyspnea (25.1%), fever (11.7%), prematurity (10.8%), collapse (9.4%), angina (7.6%), and cough (7.2%).
Dyspnea represents a cardinal symptom of both cardiovascular and respiratory disease, which are the two main causes of SD affecting 83.8% of our cases.
The most important single direct cause of SD was cardiovascular disease (59.1%) and this is consistent with the findings reported from the developed countries.
The analysis of US national and state-specific SCD data determined that 63.4% of all cardiac death cases were SCD.

19. CONCLUSIONS:
In this retrospective study, the natural SD represents 17.5% of the total deaths during the 6-year study period in KFHU, Al-Khobar, Eastern region, Saudi Arabia.
SD was more common among men than women (56% vs.42%), and the highest incidence was among the two age extremes i.e., in the elderly above 60 years and infants below 1 year (31.4% and 31.2% respectively).
There was a seasonal variation of SD with the highest incidence occurring in spring season (29.1%)and the lowest ocurring during winter months.
The most frequent prodromal symptoms were: Dyspnea, fever, collapse and angina.
Cardiovascular disease mainly acute myocardial infarction, CHD, and stroke remained the most common cause of SD in our study (59% of the cases).

20. Primary P OF S. D.
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